Metronome



April 29, 1941. w R KQCH 2,240,305

METRONOME' Filed Dec. 28, 1939 w l in Z6 Z6 3nncntor Gttorneg Patented Apr. 29, 1941 METRONOME Winfield a. Koch, Haddonfleld, N. 1., assignor e. Radio Corporation of America, a corporation of Delaware Application December as, 1939, Serial No. 311,341

9 Claims. 01. 58-130) This invention relates to a metronome and more particularly to a type of metronome which is adapted to be operated from a phonograph motor or similar device.

The conventional Maelzel type of metronome which is widely used has a number of disadvantages, the main one beingthat it requires winding from time to time and it has a slight variatime in speed depending on the degree to which it is Wound. It is highly desirable that a metronome should operate at a perfectly uniform speed and without requiring any attention from the person using it as any such attention has a tendency to distract him from the music. It is also desirable that the instrument should be capable of regulation as to volume of the sound produced so that it may be used by an individual playing softly or may even be used by an entire orchestra. It is further desirable that the device be so constructed that earphones or similar devices may be connected thereto so that the player or-players may follow the time of the metronome exactly without its sound being audible to the audience or to a recording apparatus. This latter feature is particularly desirable in connectlon with making music recordings which are to be synchronized with motion pictures.

I accomplish all of the foregoing results by providing a metronome attachment for a phonograph. When this attachment ,is used with an electric phonograph the speed of the signals is determined by the rotation of the phonograph turntable and, therefore, remains perfectly uniform and the output of the device is fed through the amplifier of the phonograph. The volume of Figure 1, showing the apparatus partly in section, and

Figure 3 is an enlarged view 01' the cam wheel of the device.

Referring first to Figs. 1 and 2, the usual phonograph is provided having a turntable Ill with a centering pin ii, the turntable being driven by the motor l2 mounted on the motor board #3. Although an electrically driven phonograph is illustrated, it will be apparent that a mechanical phonograph may be used instead. The phonograph is provided with the usual pickup 2t and tone arm 28, and here again it will be apparent that although an electro-magnetic pickup is illustrated, any other type of pickup may be used either electrical or mechanical and the output may be determined by the volume the performers.

One object of the invention is to provide an improved metronome.

Another object is to provide an attachment for a phonograph by which the device may be used as a metronome.

Another object is to provide a metronome attachment which may be applied to a phonograph and actuated by the phonograph turntable.

Another object of the invention is to provide a metronome which can reproduce sounds through the amplifier of an electric phonograph.

Other and incidental objects of the invention will be apparen to those skilled in the art from a reading of the following specification and an inspection of the accompanying drawing in which:

Figure 1 is a top view of one form of my lnvention as applied to a phonograph,

Figure 2 is a view taken from the bottom oi although in the apparatus illustrated a pickup for a laterally cut record is shown, a pickup for a vertically cut record may be used instead with an appropriate cam.

The metronome attachment includes a disc it which is shown as provided with a multiplicity of concentric grooves. These grooves are provided for ease in adjustment as will be described hereinafter but an ordinary phonograph record may be substituted for this disc under certain circumstances. In the mechanical portion of the attachment, asupporting post 15 is provided which may be secured to the motor board I3 by the base l6 screwed thereto. Alternatively, the base may be made relatively heavy as indicated in dotted lines at ll and may be merely stood on the motor board instead of being fastened thereto. A shaft i8 is appropriately jourrialed in the support 55 and if the support i5 is permanently secured to the motor board, the shaft 18 should be removable therefrom. If, however. the support is removable, the shaft l8 may be permanently secured in the appropriate bearings in the support l5. The other end of the shaft runs in a bearing in a member I9 which fits over the pin II in the turntable ill. The shaft [8 may be secured against longitudinal movement in the member is by appropriate collars 3t and 3|.

The shaft l8 carries a wheel. 2| mounted on an appropriate sleeve 20 which is adapted to be secured to the shaft IS at any desired point, as for example, by thawingscrew 22. The wheel 2! may be provided with a tire of rubber or other appropriate material which will provide proper friction with the disc l4 and will at the same time prevent noise during rotation thereof. It will be apparent that rotation of the turntable ill and disc M will cause rotation of the wheel 2i and, therefore, of the shaft I8. The speed of this rotation will obviously depend on which of the grooves in the disc M carries the wheel 2!. If the wheel is in the innermost groove, the Wheel it will rotate very slowly audit the turntable I0 is rotated at the usualspeed or approxi.

mately 78 R. P. M. the shaft II will rotate at the usual lowest metronome speed of 40 revolutions per minute and give one click for each revolution of the shaft l8. If the wheel 2| is placed in one of the grooves or tracks of larger diameter, the shaft II will rotate at a correspondingly greater speed. It will be apparent that the grooves in the disc ll may each be marked with the shaft speed which will correspond thereto, or alternatively the speed calibration may be marked directly on the shaft ll and the latter is preferable if the device is to be used with ordinary phonograph records having no tracks therein. It will also be apparent that any other appropriate securing means may be substituted for the wing screw 22 provided that the means secures the wheel 2| and shaft II against relative rotation and maintains the wheel 2! in a fixed position longitudinally of the shaft. For example, the sleeve might be keyed to the shaft l8 or a square shaft might be used, and any appropriate type of latch might be used to secure the sleeve 20 at appropriate longitudinal positions.

The cam wheel 23 is provided with an appropriate groove 24 in which the needle of the pickup 21 may rest. As shown in Fig. 2 the groove 24 is provided with a slight sideways jog 32 which causes a sudden sideways movement of the needle once for each rotation of the shaft I8, thereby causing the production of a click by the phonograph and the speed of these clicks will, as described above, depend on the position of the wheel 2|.

As shown in Fig. 3, the cam wheel 23 may be provided with additional grooves 25 and 28 provided with, for example, two jogs and three jogs respectively,. thereby producing clicks at two or three times the speed of rotation of the shaft i8 and giving a correspondingly greater range of speed to the apparatus. This increased speed is sometimes highly desirable for the reason that although the highest speed normally provided by a metronome is 208 clicks per minute, it is sometimes desirable to provide an individual click for each of the notes or fractions thereof in a measure as, for example, in a march time of 120 per minute if there were three or four notes to the beat, it might be desirable to provide 360 or 480beats per minute as the case might be.

The cam 23 may be provided with a number of cam tracks corresponding to the number of beats in a measure. For example, it may be provided with 5 tracks corresponding to 1, 2, 3, 4 and 6 beats, respectively, which are the usual numbersof beats per measure, and in each track there may be a single jog which is so cut as to either shape or depth as to produce a louder sound than the others, thus accenting the first beat of each measure.

It will be apparent that in the application of my invention to an electric phonograph, as illustrated, the volume of the sounds reproduced may be regulated by the usual volume control of the phonograph. Further, since electric phonographs are usually provided with a thermionic amplifier, the output of the amplifier may be used in any manner desired either to operate a loudspeaker or to operate earphones, as described above.

Having now described my invention, I claim:

1. A metronome attachment for phonographs including means adapted to be driven by the phonograph turntable at predetermined speeds, and means connected to said means for actuating the phonograph pickup in accordance with said speeds.

' 2 A metronome attachment for phonographs including means adapted to be driven by the phonograph turntable at predetermined speeds, and means connected to said means and adapted to cooperate with a phonograph pick-up for actuating the phonograph pick-up in accordance with said speeds.

3. A metronome attachment for phonographs including means adapted to be driven by the phonograph turntable at predetermined speeds, means connected to said means foractuating the phonograph pick-up in accordance with said speeds, and a driving disc on said turntable having concentric tracks corresponding to different metronome speeds.

4. A metronome attachment for phonographs including a wheel adapted to be driven by the phonograph turntable at predetermined speeds, means adapted to actuate a phonograph pickup at predetermined intervals, and means connecting said wheel and said actuating means whereby the pickup will be actuated at predetermined speeds and at predetermined intervals.

5. A metronome attachment for phonographs including a wheel adapted to be driven by the phonograph turntable at predetermined speeds, a cam adapted to actuate a phonograph pickup at predetermined intervals, and means connecting said wheel and said cam whereby the pickup will be actuated at predetermined speeds and at predetermined intervals.

6. A metronome attachment for phonographs including a wheel adapted to .be driven by the phonograph turntable at predetermined speeds, a cam having a plurality of cam tracks adapted to actuate a phonograph pickup at different predetermined intervals, and means connecting said wheel and said cam whereby the pickup will be actuated at predetermined speeds and at predetermined intervals.

7. Apparatus of the class described including a shaft adapted to be supported radially over a phonograph turntable, means for supporting said shaft, means adjustable on said shaft for driving said shaft from the phonograph turntable, and means on said shaft adapted to cooperate with the phonograph reproducer for producing sounds over said reproducer in accordance with the rotation of said shaft.

8. Apparatus of the class described including a shaft adapted to be supported radially over a phonograph turntable, means for supporting said shaft, means adjustable on said shaft for driving said shaft from the phonograph turntable, means for fixing said driving means to said shaft, and means on said shaft adapted to cooperate with the phonograph reproducer for producing sounds over said reproducer in accordance with the rotation of said shaft.

9. Apparatus of the class described including a shaft adapted to be supported radially over a phonograph turntable, means for supporting said shaft, means adjustable on said shaft for driving said shaft from the phonograph turntable, and cam means on said shaft adapted to cooperate with the phonograph reproducer for producing sounds over said reproducer in accordance with the rotation of said shaft, said cam means having a plurality of cam tracks adapted to produce different numbers of sounds per revolution of the shaft.

WINF'IELD R. KOCH. 

